I would be good to have a number of combat formations.
a) support ships to the rear
b ) support ships protecting capital ships only
c) Heavy combat ships to the rear (meat shields)
d) All round defense - for passing through systems and getting shot in the rear
e) cruiser detachements - that can raid while the main fleet concentrates.
etc
f) Convoy mode - escort the trade ships
g) Raid and regroup mode - allows smaller ships to break off at targets of opportunity
h) Pure defence mode. The hedgehog....
i) Keep your distance - fleet avoids close combat to use long range advantage. This also has the advantage of keeping the fleet cohesive.
j) Close combat - get in under their guns. The odds are more even their. Carronades anyone?
k) 120% reactors on all ships - Drop slow and damaged ships from formation and push engine overload. bolt for it.
l) Smash through - Ram enemy ships - kamikaze style - this could get annoying though.